> Java needs to generates a lot of garbage, whereas C++ does not. Therefore, GC for C++ can be simpler and generate lower overhead than GC for Java.
You mean lower footprint overhead; higher performance overhead. But that was my point: Higher-level, high-performance languages that rely on good abstraction -- like Java, C# and Go -- need a better-performing GC, which is why they choose tracing, and pay for it with more footprint. In terms of performance, tracing used in industry beats refcounting as used in industry.
> I'm interested in code performance
Sure, but you have to pay for: either with a higher footprint or with higher maintenance costs.
> Are you aware of any other absolutely zero pause GCs?
The ones I know of are ZGC and Azul's C4, which preceded ZGC by some years but was not open-sourced. ZGC isn't some obscure technology, BTW. It is currently running most of Netflix's workload, and probably other very large companies.
(Also, ZGC, does no collection work in pauses; it does pause threads to synchronise a state transition but for durations similar to those that the OS also pauses threads for).
As their goal was a language that would be very popular, and given that languages that heavily rely on GC have many times more users than languages that don't, it doesn't seem that they were wrong, at least not about the centrality of GC (although, "value types" and arrays-of-structs are coming to Java).
> SGCL never pause threads, so it can collect garbage more often and more efficiently.
I can't examine the algorithm right now and I couldn't find a paper describing it (so I can't tell you if it's one of the algorithms we've tried), but if you believe you have a more efficient GC than those in the JDK, feel free to plug it in and test. If you're right, you'll have many millions of users and the overall impact of that algorithm on the software industry would be much greater than it would as a C++ GC.
You mean lower footprint overhead; higher performance overhead. But that was my point: Higher-level, high-performance languages that rely on good abstraction -- like Java, C# and Go -- need a better-performing GC, which is why they choose tracing, and pay for it with more footprint. In terms of performance, tracing used in industry beats refcounting as used in industry.
> I'm interested in code performance
Sure, but you have to pay for: either with a higher footprint or with higher maintenance costs.
> Are you aware of any other absolutely zero pause GCs?
The ones I know of are ZGC and Azul's C4, which preceded ZGC by some years but was not open-sourced. ZGC isn't some obscure technology, BTW. It is currently running most of Netflix's workload, and probably other very large companies.
(Also, ZGC, does no collection work in pauses; it does pause threads to synchronise a state transition but for durations similar to those that the OS also pauses threads for).